A working system for a circuit substrate is a system for performing a predetermined operation for a circuit substrate, and is, for example, an electronic-circuit-component mounting system for mounting electronic circuit components as components of an electronic circuit on a printed-wiring board, or a highly-viscous fluid coating system for coating a printed-wiring board with a highly viscous fluid such as an adhesive. As one kind of such a working system for a circuit substrate, there is known a system comprising: (a) a substrate conveyor capable of conveying a circuit substrate along a straight line in a conveying direction, and of stopping the circuit substrate at a desired position in the conveying direction; (b) a moving apparatus having a first movable member which is movable in the conveying direction and a second movable member which is movable in a direction intersecting with the conveying direction, the moving apparatus being capable of moving the second movable member to a desired location in a plane; and (c) a working head which is held by the second movable member and performs a plurality of operations for prescribed points on the circuit substrate stopped as indicated above. In such a type of system, the circuit substrate is conveyed by the substrate conveyor and stopped at a position where to perform the operation.
Therefore, the conventional system has at least one of a stopper and a sensor for stopping the circuit substrate. The stopper is moved by the moving apparatus to its operative position located in a path of conveyance along which the circuit substrate is conveyed, and to its inoperative position away from the path of conveyance. When the circuit substrate is carried into the working system, the stopper is located at the operative position to be brought into contact with the circuit substrate to stop the circuit substrate. For example, the sensor consists of two pairs of sensors which pairs are spaced from each other in the conveying direction, and is adapted such that the conveyance of the circuit substrate is decelerated when one of the two pairs of sensors located on the upstream side in the conveying direction detects the circuit substrate, and the circuit substrate is stopped when the other pair of sensors located downstream detects the circuit substrate.
Such a stopper or sensor is disposed in a main body of the working system, at a fixed position in most cases, and the circuit substrate is stopped at a stop position in relation to a predetermined position of a contact portion, or of a detection portion which is to be detected by the sensor. The stopper or sensor may be disposed such that its location in the conveying direction in which the circuit substrate is conveyed is adjustable, and an operator adjusts the location of the stopper or sensor so that the circuit substrate is stopped at an appropriate position.